19.2 Pediatric Restorative Dentistry, Pulpal Therapy, and Dental Trauma

9.3 Pediatric Restorative Dentistry, Pulpal Therapy, and Dental Trauma

Primary Tooth Restorative Dentistry

Restorative dentistry in primary teeth requires modified preparation principles due to unique anatomical features: thinner enamel and dentin layers (half the thickness of permanent teeth), larger pulpal horns located closer to the tooth surface, prominent cervical constrictions, and broad interproximal contact areas.

Direct Restorations & Anterior Strip Crowns

1. Composite Resin & Glass Ionomer Restorations:
   • Indication: Small-to-moderate Class I and Class II restorations where adequate isolation can be maintained.
   • Resin-Modified Glass Ionomer (RMGI): Ideal for high-caries-risk children due to continuous fluoride release and chemical adhesion to enamel and dentin without requiring micro-mechanical resin tags.
2. Anterior Strip Crowns:
   • Clear celluloid crown forms filled with composite resin, indicated for severe multi-surface or rampant decay on primary anterior teeth.
   • Preparation: Reduces incisal length by 1.5–2.0 mm, interproximal slices, and circumferential subgingival chamfer or feather-edge margin.

Stainless Steel Crowns (SSCs)

Pre-formed chrome-steel full-coverage crowns represent the most durable restorative modality for primary molars, exhibiting superior clinical longevity compared to multi-surface amalgam or composite restorations.

Stainless Steel Crown (SSC) Preparation Steps:
1. Occlusal Reduction: 1.0–1.5 mm following occlusal anatomy
2. Interproximal Slicing: Vertical cuts with knife-edge margin (NO LEDGE!)
3. Buccal/Lingual Surfaces: Minimal reduction, preserving cervical bulge
4. Selection & Fitting: Try smallest crown size restoring mesiodistal width
5. Contouring & Crimping: 114 pliers (contour) + 115 pliers (crimp margin)
6. Cementation: Glass ionomer or RMGI cement; seat lingual-to-buccal

• Primary Indications:
  • Primary molars with multi-surface caries or extensive lesions spanning past line angles.
  • Coronal restoration following vital pulpotomy or pulpectomy.
  • Teeth with extensive developmental enamel/dentin defects (amelogenesis imperfecta, dentinogenesis imperfecta, hypoplasia).
  • Abutments for space maintainers (e.g., crown loop).
  • High-risk uncooperative pediatric patients treated under general anesthesia.
• Tooth Preparation Principles (HIGH YIELD FOR INBDE):
  • Occlusal Reduction: 1.0 to 1.5 mm uniform reduction following functional cuspal contours to maintain clearance.
  • Interproximal Reduction: Vertical slicing with a tapered diamond bur creating a feather-edge (knife-edge) subgingival margin. Strict Exam Rule: Do NOT prepare a ledge or shoulder! Ledges prevent full seating of the crown margin.
  • Buccal and Lingual Surfaces: Minimal or no reduction. The prominent buccal cervical bulge must be preserved because it provides the essential mechanical undercut into which the crown snaps.
  • Crown Selection & Adjustment: Select the smallest crown size that restores mesiodistal arch distance. Trim crown margins 1 mm below the free gingival margin.
  • Contouring & Crimping:
    • 114 Contouring Pliers (Gordon Pliers): Used to shape and accentuate the middle third of the crown walls.
    • 115 Crimping Pliers (Pink/Blue Handle Pliers): Used to crimp the gingival 1 mm margin inward $360^\circ$ to establish a tight mechanical snap-fit over the buccal cervical bulge.
  • Cementation: Fill crown with Glass Ionomer or RMGI cement. Seat crown from lingual to buccal to squeeze excess cement out anteriorly and prevent tissue entrapment.

---

Primary Tooth Pulpal Therapy

Primary pulp therapy preserves primary teeth in a disease-free state until normal physiological exfoliation.

Primary Pulp Therapy Decision Tree:
                     [ Tooth Exposure / Caries ]
                                  |
           -------------------------------------------------
          |                                                 |
  [ Vital Pulp / Reversible ]                  [ Necrotic / Irreversible ]
          |                                                 |
[ Bleeding stops < 5 min ]                        [ Constant Pain / Pus / Furcation Loss ]
          |                                                 |
  ( Vital Pulpotomy )                               ( Pulpectomy + Resorbable Paste )

Direct Pulp Capping (DPC)

• Strict Clinical Rule: Direct pulp capping is CONTRAINDICATED in primary teeth with carious pulp exposures! Carious exposures in primary pulp consistently trigger chronic inflammation, internal root resorption, and apical abscess formation. Direct pulp capping is strictly limited to tiny, non-carious mechanical pinhole exposures (e.g., traumatic or accidental mechanical pulp exposure) in completely asymptomatic teeth under rubber dam isolation.

Vital Pulpotomy

Removal of the inflamed coronal pulp tissue down to the radicular pulp orifices, preserving vital, uninflamed radicular pulp tissue.

• Indications: Reversible pulpitis, mechanical exposure, or carious exposure in a primary tooth with normal root structures and no history of spontaneous pain.
• Procedure & Hemostasis Standard:
  1. Remove coronal pulp using a high-speed round bur or sharp spoon excavator down to the floor of the pulp chamber.
  2. Apply a sterile, moist cotton pellet with light pressure directly onto the radicular pulp orifices for 2 to 5 minutes.
  3. Critical Clinical Decision: If bleeding stops within 2 to 5 minutes and is bright red, the radicular pulp is healthy $ ightarrow$ Proceed with pulpotomy medicament. If bleeding is dark, hyperemic, or fails to stop after 5 minutes, the radicular pulp is irreversibly inflamed or necrotic $ ightarrow$ Abandon pulpotomy and perform pulpectomy.
• Pulpotomy Medicaments & Histologic Effects:
  • Formocresol Pulpotomy:
    • Composition: 1/5 dilution of Buckley's Formocresol (19% formaldehyde, 35% cresol in 15% glycerin and water).
    • Protocol: Place cotton pellet moistened with 1/5 formocresol over radicular stumps for 5 minutes.
    • Three Histologic Zones Created:
      1. Zone of Fixation (Coronal third): Formalin fixative produces acidophilic, non-viable tissue.
      2. Zone of Atrophy (Middle third): Pale-staining, cellular degeneration.
      3. Zone of Vital Tissue (Apical third): Normal, viable radicular pulp tissue.
  • Ferric Sulfate (15.5%): Non-aldehyde hemostatic agent. Agglutinates blood proteins without cell fixation, forming a protective ferric-protein plug over orifices. Safe, effective alternative to formocresol.
  • Mineral Trioxide Aggregate (MTA): Gold-standard biocompatible material for primary pulpotomy. MTA releases calcium hydroxide, stimulates cytokine production (TGF-$eta$), and promotes true dentine bridge formation with superior long-term clinical success rates ($>95%$).
  • Sodium Hypochlorite (1.5%–3% NaOCl): Used as a disinfecting hemostatic agent prior to placing MTA or GIC.

Pulpectomy (Non-Vital Root Canal Therapy)

Complete debridement of coronal and radicular pulp channels, indicated for non-vital primary teeth.

• Indications: Primary teeth exhibiting pulpal necrosis, irreversible pulpitis, furcal radiolucency, soft tissue swelling, or uncontrollable radicular hemorrhage during pulpotomy.
• Procedure: Instrument canals short of the radiographic apex (1–2 mm short) to avoid damaging the underlying permanent tooth germ. Irrigate with 1% NaOCl.
• Obturation Material Rule (HIGH YIELD):
  • Canals MUST be obturated with a RESORBABLE PASTE whose resorption rate matches the physiological root resorption of the primary tooth!
  • Acceptable Materials: Unreinforced Zinc Oxide Eugenol (ZOE) without setting accelerators, Vitapex (Calcium hydroxide and Iodoform paste), or Endoflas.
  • Exam Trap / Warning: NEVER use non-resorbable gutta-percha or resin sealers in primary teeth! Non-resorbable materials physically block the eruption path of the underlying permanent successor, causing severe impaction or ectopic eruption.

---

Primary Space Maintainers & Eruption Guidance

Premature loss of primary teeth permits mesial drift of adjacent posterior teeth, leading to loss of arch perimeter, crowding, and permanent tooth impaction.

Clinical Decision Making & Eruption Timing

• Space maintainers are indicated when a primary tooth is lost prematurely and the permanent successor is NOT ready to erupt.
• Rule of Thumb: A permanent tooth typically erupts when two-thirds ($2/3$) of its root development is complete. If more than 1 mm of bone covers the unerupted permanent tooth, eruption will take at least 6 months.

Space Maintainer Classification & Clinical Rules

---

Traumatic Dental Injuries: Primary vs. Permanent Dentition

Traumatic injuries in children require distinct management strategies depending on whether the injured tooth is primary or permanent.

Avulsion Management Rules

Avulsion is the complete displacement of a tooth out of its alveolar socket.

Avulsion Decision Rationale:
PRIMARY TEETH   --> NEVER REPLANT! (Risk damaging underlying permanent germ / ankylosis)
PERMANENT TEETH --> REPLANT IMMEDIATELY! (Goal: Preserve PDL cell viability)
                    Storage Media: HBSS > Cold Milk > Saline > Saliva >>> Tap Water
                    Splinting: 2-week flexible splint

• Avulsed Primary Teeth: NEVER REPLANT AN AVULSED PRIMARY TOOTH!
  • Rationale: Replantation risks introducing infection, causing ankylosis, or directly damaging the underlying permanent tooth germ (leading to Turner's hypoplasia or crown dilaceration).
• Avulsed Permanent Teeth: Replant immediately at the scene if possible!
  • Critical Time Window: Replantation within 30 to 60 minutes provides the highest probability of periodontal ligament (PDL) cell survival. If extra-oral dry time exceeds 60 minutes, PDL cells are necrotic; ankylosis and replacement resorption are inevitable.
  • Storage Media Hierarchy:
    1. Hank's Balanced Salt Solution (HBSS): Gold standard; maintains cell viability for up to 24 hours.
    2. Cold Milk: Excellent, readily available medium; maintains osmolality for 2 to 6 hours.
    3. Saline Solution: Acceptable short-term storage.
    4. Patient's Saliva (in buccal vestibule): Acceptable if no liquid is available.
    5. Tap Water (DO NOT USE): Hypotonic solution causing rapid PDL cell lysis and cell death.
  • Handling: Hold tooth by CROWN ONLY. Do not touch, scrub, or scrape root surfaces.
  • Management by Apex Status:
    • Open Apex (Immature Tooth): High potential for pulpal revascularization. Replant, apply flexible splint, and monitor closely. Avoid immediate root canal therapy unless clinical/radiographic necrosis develops.
    • Closed Apex (Mature Tooth): Perform root canal therapy within 7 to 10 days post-replantation to prevent inflammatory root resorption.
  • Splinting: Apply a flexible (non-rigid) splint for 2 weeks.

Intrusion Injury Management

Intrusion is the apical displacement of a tooth deeper into alveolar bone, crushing PDL fibers and socket bone.

• Intruded Primary Teeth:
  • Take an anterior lateral radiograph to determine the directional trajectory of the primary root apex:
    1. Root Apex Displaced LABIALLY (away from permanent tooth germ): Leave for spontaneous re-eruption. Monitor clinically and radiographically for 2 to 6 months.
    2. Root Apex Displaced LINGUALLY (impinging directly on permanent tooth follicle): EXTRACT IMMEDIATELY to protect the permanent successor.
• Intruded Permanent Teeth:
  • Immature / Open Apex: Monitor for spontaneous re-eruption.
  • Mature / Closed Apex: Reposition orthodontically or surgically, and initiate root canal therapy within 2 weeks.

Luxation Injuries & Splinting Guidelines

• Concussion: Tooth sensitive to percussion, no mobility, no displacement. No treatment required; soft diet and monitor.
• Subluxation: Increased mobility, sulcular bleeding, no displacement. Soft diet, monitor; splint for 2 weeks only if symptomatic.
• Extrusive Luxation: Partial displacement of tooth out of socket. Reposition gently and place a flexible splint for 2 weeks.
• Lateral Luxation: Eccentric displacement of tooth (usually crown lingual, apex labial). Reposition gently and place a flexible splint for 4 weeks (or 2 weeks for minor displacement).

Splinting Duration Protocols Summary Table